This article examines the role of psychiatry in the life and work of Frantz Fanon. It focuses on Fanon's relationship to institutional psychotherapy, which he discovered at the hospital of Saint-Alban through the figure of François Tosquelles. Institutional psychotherapy confirmed, on a clinical level, what Fanon had already intuited in his early work. If alienation was always political and psychic at the same time, then decolonization needed to involve the disalienation of the mind. This is precisely what Fanon tried to do in his psychiatric work in North Africa and in his last political texts.